1. Field of the Invention
The present invention relates to a storage system including a plurality of battery modules.
2. Description of the Related Art
A storage system including a plurality of battery modules has been well known. The battery modules are each generally provided with a battery, and a charger that makes a supply of direct current from a power source to the battery. When a power failure or any power source failure occurs, with power provided by the battery modules, data stored in a volatile memory, e.g., cache memory, is backed up on nonvolatile storage resources, e.g., hard disk or flash memory.
Patent Document 1 (JP-A-9-215217) describes a battery charging device that can charge a plurality of batteries. Patent Document 2 (JP-A-10-271705) describes a power source circuit provided with a charging circuit that supplies a charging current to a battery in a battery pack. Patent Document 3 (JP-A-2002-78227) describes a battery charging control device that controls both an electronic device and a power supply to a battery in accordance with a priority over operation or battery charging.
A storage system desirably has the lower rated power consumption. As an improvement therefor, charging control over the storage system, i.e., a plurality of batteries in a plurality of battery modules, is worthy of note.
The concern here is that none of above Patent Documents 1 to 3 describes a technology applicable to charging control over such a storage system, i.e., the batteries in the battery modules. That is, Patent Documents 1 merely describes one battery module, i.e., battery charging device, and Patent Document 2 merely describes one battery module, i.e., battery pack. Patent Document 3 merely describes one battery.